1. Field of the Invention
The present invention relates generally to the art of trays and in particular to stackable trays which may be used to contain, transport and display a variety of food and other products.
2. Description of the Prior Art
Various types of trays, baskets and tote boxes are commonly utilized to transport products at production facilities and to and from the distribution system. Such trays and baskets are especially common in the food industry. For example, bakeries use such trays to transport bread products to grocery stores. Produce distributors use them to transport produce, and butchers use them to transport portioned meat.
In the bakery industry, trays are typically used for transporting bread, and baskets are used for transporting buns, cakes, pastry, rolls, etc. The trays and baskets may be interchangeable, but as a rule, this only occurs when there is a temporary shortage of a specific tray or basket. These types of trays or baskets may be constructed of wire form, steel draw forms or molded plastic and are manufactured in a variety of sizes and heights to accommodate a wide variety of products. As a general rule, such trays and baskets may be stacked for reasons which will be discussed later in this specification.
Greater detail will now be provided concerning the trays and baskets used in the bakery industry. It should be understood at the outset, however, that such description is provided for purposes of illustration rather than for limitation. One skilled in the art could readily adapt the principles of the present invention to a wide variety of food and non-food items after reading the present specification. For example, many industrial applications exist where stackable trays may be used to convey parts or components from one part of a plant to another part of a plant or such stackable trays may be used to store completed parts or assemblies. Many of the problems encountered with prior art bakery trays and baskets are also encountered in such industrial applications, so the present invention will be equally applicable thereto.
Common bread trays are about 20-22 inches in width, 26-30 inches in length and are about 1-1.5 inches high. They are similar in many ways to common cafeteria type trays, with diverging front, rear and side walls to permit nesting (similar to the way paper cups nest). The baskets most commonly employed are constructed of wire and have measurements similar to bread trays but come in a variety of heights to accommodate the particular type of bakery product they are designed to hold, for example, between about 21/2-51/2 inches. These wireform baskets do not nest the way bread trays do, but instead they stack.
Bakery trays and baskets are employed in the manufacturing plant to contain and transport product on conveyor lines and in mobile carts known as halfracks. They are also used in automatic and manual handling systems at the shipping docks at the plant.
Halfracks usually hold about 28 trays or baskets and are loaded at the plant for subsequent delivery of the product to semi-trailers or delivery vans. Smaller vans and route trucks also typically have a halfrack arrangement, but these are not mobile. Instead, they are permanently mounted in the interior storage area of the truck or van. Such halfracks are generally quite heavy and their elimination would result in reduced fuel consumption and a consequent savings in product transportation cost.
Once the bakery trays or baskets leave the plant, they continue to be used in the transportation and product distribution system. Loaded halfracks are moved from a conveyor system onto the semi-trailers where they are delivered to route trucks. At this point the trays or baskets are loaded into the route trucks to transport the goods to wholesale or retail outlets. At the sales outlet, the trays or baskets are used to carry the product from the trucks to the display area and are frequently used for on-floor display. If not, the trays and baskets are unloaded and the empty trays are loaded back on the route trucks.
To fully appreciate the importance of the trays or baskets in the product distribution system, it is necessary to first understand that the business is one of extremely high volume, where cost and efficiency have a great impact on profitability. It is most advantegeous to load delivery trucks to maximum capacity. But it must also be remembered that the delivery trucks pick up return baskets or trays on a daily basis to feed them back into the product handling system. The logistics of the system can easily be upset as illustrated by the following example. If a fully loaded truck makes its first delivery and unloads ten trays or baskets, but finds twenty empty trays or baskets, an impossible situation exists unless the trays or baskets have some nesting capability. The random sequence of delivering loaded trays and picking up empty trays makes this problem one which is encountered on a daily basis.
Some commercially available trays have moving parts to provide a nesting capability. However, because trays and baskets are handled so frequently, such trays or baskets can easily become damaged. Plastic baskets are available with moving flaps to provide various stacking heights, but damage to one of the moving parts will render the entire tray unusable for its intended function. Further, some trays or baskets are available which achieve various stacking heights through rotation of the basket by 90.degree. or 180.degree.. The handling of such baskets requires additional time, thereby decreasing the overall efficiency of the distribution system.
Several of such trays are described in issued U.S. Letters Patents Wilson, in his U.S. Letters Pat. No. 4,308,954, issued Jan. 5, 1982 for "Plastic Nestable-Stackable Receptacle", describes a tray for bakery or other products which may be stacked without the need to slide or rotate the receptacles with respect to one another. The tray is generally U-shaped and includes a plurality of projections which extend upwardly from the top of the side walls and several rows of slots in the side walls and below the projections. The trays may be stacked one on top of the other or nested by inserting the projections of a lower tray into the slots of the upper tray. The height is selected by the row of slots chosen. This patent does not relate to baskets or trays which may be stacked or nested at more than two heights. Furthermore, the projections and slots can be damaged during use, preventing the nesting or stacking capability, and the alignment of projections with slots requires time which decreases distribution system efficiency.
Thurman, in his U.S. Letters Pat. No. 4,238,032, issued Dec. 9, 1980 for "Three-Position Stacking Tray", describes a tray which again is generally U-shaped and which includes a series of parallel but angled ribs on each of the tray's side walls. Each rib includes a notch on a side surface, approximately half way between the top and the bottom of the tray. The ribs of one side are also arranged in mirror relationship to the ribs on the other side. The three height capability is accomplished by reversing the trays 180.degree. for one height and by the type of vertical movement employed when the trays are assembled. The reversal of tray orientation and manipulation in assembly (to ensure that the notches seat property) is time consuming and reduces the efficiency of distribution involving such trays.
Another multi-position container is described in the Carroll et al. U.S. Letters Pat. Nos. 4,102,453 and 4,320,837 issued respectively on July 25, 1978 and Mar. 23, 1982 for "Nesting and Stacking Containers." These patents also describe U-shaped trays which include features which permit the trays to be stacked in three positions without rotating one container with respect to another. This is accomplished by providing side walls having an upper rail and a plurality of bars extending along the outside of the side walls and inclined downwardly, each bar having a stacking foot formed on the bottom thereof. The top of each bar forms a stacking saddle. The angle of each bar is selected so that the foot of one bar can nest in the saddle of an adjacent bar to provide a high-nest stacking position. The lowermost stacking position is accomplished when the bars slide between one another. An intermediate position is made possible by providing stacking supports intermediate the ends of the bars which are cup-like supports and act like the saddles described above. A back wall of the tray also includes inclined bars to assist in the stacking. The Carroll device is quite complex and the inclined bars and various saddle supports are subject to damage rendering the trays useless. Furthermore, the alignment of the trays to obtain the desired stocking height is relatively time consuming.
Wilson describes a "Meat Lug" in U.S. Letters Pat. No. 3,027,045 issued Mar. 27, 1962 which is capable of being stacked at two levels. The lug has four ribs molded into its side walls and a pair of notches formed in the top surface of the lug on either side of the ribs. The lugs are nested by having the ribs slide into the ribs of a lower lug and are stacked by placing the bottom of the ribs of the upper tray into the notches of a lower tray. In the stacking positions, the lugs are alternatively placed in different ones of the pair of notches to maintain stability. The lugs cannot be stacked at three levels.
Finally, Sanders et al., in U.S. Letters Pat. No. 4,000,817 issued Jan. 4, 1977 describe a "Three Level Stacking Container" which includes stacking feet formed on an exterior tray wall and saddles on the top of the interior of the walls and at two levels for supporting the feet. The feet are generally L-shaped and the determination of the stacking level is established by the orientation of the trays. In addition, the trays must be tilted somewhat to accomplish insertion of the feet into the saddles. The Sanders et al. tray is also generally U-shaped.
A tray which overcomes the aforementioned disadvantage of the prior art would represent a significant advance in this art. Ideally, such a tray should nest at its lowest stacking height, should have at least three stacking heights, should allow for maximum product visability and accessability, should be stable when stacked, should be adaptable to current conveyor and product handling systems, should have durability, should have no moving parts and should be as light in weight as possible.